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Fluorescence Aptameric Sensor for Strand Displacement Amplification Detection of Cocaine

A new fluorescence method based on aptamer-target interactions has been developed for cocaine detection with target-induced strand displacement. Here we describe new probes, the hairpin-probe and the single strand-probe (ss-probe), that possess two recognition sequences of cocaine aptamer. In the pr...

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Bibliographic Details
Published in:Analytical chemistry (Washington) 2010-02, Vol.82 (4), p.1358-1364
Main Authors: He, Jing-Lin, Wu, Zai-Sheng, Zhou, Hui, Wang, Hong-Qi, Jiang, Jian-Hui, Shen, Guo-Li, Yu, Ru-Qin
Format: Article
Language:English
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Summary:A new fluorescence method based on aptamer-target interactions has been developed for cocaine detection with target-induced strand displacement. Here we describe new probes, the hairpin-probe and the single strand-probe (ss-probe), that possess two recognition sequences of cocaine aptamer. In the presence of cocaine, both probes would associate with the target to form a tripartite complex. The conformational change in the hairpin-probe causes the opening of a hairpin structure and the hybridization to primer. With polymerase and the dNTPs, the replication of the single-stranded domain of hairpin-probe triggers the process of primer extension. When the hairpin-probe is converted into a fully double-stranded form, the ss-probe and cocaine are displaced to bind another hairpin-probe and initiate new amplification cycles. Fluorescence signal generation would be observed upon SYBR Green I intercalating into the new DNA double helix. The new protocol design permits detection of as low as 2 nM cocaine in a closed tube, offering a convenient approach for a homogeneous assay. Compared with previously reported cocaine aptameric sensors, our new method is highly sensitive, selective, and economical.
ISSN:0003-2700
1520-6882
DOI:10.1021/ac902416u